MANHATTAN — Tom Hanks’ controversial new 9/11 movie “Extremely Loud and Incredibly Close” received a thumbs-up from a former NYPD detective commander whose brother-in-law died in the attacks on the World Trade Center — and he does not believe the movie is at all a case of Hollywood exploitation.

In fact, retired Det. Sgt. Kevin Campbell thinks the film, which opened Friday after limited release in December and drew warnings about flashbacks, is an important one that finally portrays the complex challenges faced by families who lost loved ones on that fateful day more than a decade ago.

“This movie shows you that there were a lot more victims that day than the nearly 3,000 people who died,” said Campbell, a former Bronx detective squad commander who became a key aide to former NYPD Deputy Commissioner for Operations Garry McCarthy, now Chicago’s police superintendent.

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On 9/11, Campbell’s brother-in-law, John Gallagher, was a 31-year-old energy trader for Cantor Fitzgerald working on the 105th floor of the World Trade Center, which turned out to be the exact floor where Tom Hanks becomes trapped in the film.

Gallagher was a younger brother of Campbell’s wife, Therese. He grew up in the Castle Hill section of the Bronx and attended St. Raymond’s High School, eventually graduating from Manhattan College.

On Sept. 8, 2000, Gallagher married his sweetheart, Francine. The couple celebrated their first anniversary just three days before 9/11. And they had a six-week old son, James.

On the weekend before 9/11, the Gallaghers attended a wedding with four other young couples with whom they were friends. Two of the husbands were New York City firemen, Michael Lynch and Dennis Mulligan. Like Gallagher, they too did not survive.